<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  <script src="./js/MyVue.js"></script>
  <script src="./js/Dep.js"></script>
  <script src="./js/Watcher.js"></script>
  <script>
    const app = new MyVue({
      data: {
        test: 'I an test',
        foo: {
          bar: 'bar'
        }
      }
    })
    app.$data.test = 'hello yeShang'
    app.$data.foo.bar = 'hello world'
  </script>
</body>
</html>